Charles Spurgeon Commentary John 8:31

"Jesus therefore said to those Jews that had believed him, If ye abide in my word, [then] are ye truly my disciples;" — John 8:31 (ASV)

Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed;

For there were many, in Christ's day, coming to him for a while, and then going away from him; professing to believe, and then stumbling when Christ proclaimed some doctrine which struck them as being strange and hard to receive. Our Lord Jesus tells them that constancy is necessary to true discipleship.

It is of no use to start running in the race unless we continue in the course till the prize is won. We are not true pilgrims to heaven merely because we cross the threshold of our door; we must keep on, and on, and on, till we reach the golden streets of the New Jerusalem.